1,744 research outputs found
Fault diagnosis using an improved fusion feature based on manifold learning for wind turbine transmission system
In this paper, a novel fault diagnosis method based on vibration signal analysis is proposed for fault diagnosis of bearings and gears. Firstly, the ensemble empirical mode decomposition (EEMD) is used to decompose the vibration signal into several subsequences, and a multi-entropy (ME) is proposed to make up the fusion features of the vibration signal. Secondly, an improved manifold learning algorithm, local and global preserving embedding (LGPE), is applied to compress the high-dimensional fusion feature set into a two-dimension feature set. Finally, according to the clustering accuracy of different feature set, the fault classification and diagnosis can be performed in the reduced two-dimension space. The performance of the proposed technique is tested on the fault of wind turbine transmission system. The application results indicate that the proposed method can achieve high accuracy of fault diagnosis
Maximizing Model Generalization for Machine Condition Monitoring with Self-Supervised Learning and Federated Learning
Deep Learning (DL) can diagnose faults and assess machine health from raw
condition monitoring data without manually designed statistical features.
However, practical manufacturing applications remain extremely difficult for
existing DL methods. Machine data is often unlabeled and from very few health
conditions (e.g., only normal operating data). Furthermore, models often
encounter shifts in domain as process parameters change and new categories of
faults emerge. Traditional supervised learning may struggle to learn compact,
discriminative representations that generalize to these unseen target domains
since it depends on having plentiful classes to partition the feature space
with decision boundaries. Transfer Learning (TL) with domain adaptation
attempts to adapt these models to unlabeled target domains but assumes similar
underlying structure that may not be present if new faults emerge. This study
proposes focusing on maximizing the feature generality on the source domain and
applying TL via weight transfer to copy the model to the target domain.
Specifically, Self-Supervised Learning (SSL) with Barlow Twins may produce more
discriminative features for monitoring health condition than supervised
learning by focusing on semantic properties of the data. Furthermore, Federated
Learning (FL) for distributed training may also improve generalization by
efficiently expanding the effective size and diversity of training data by
sharing information across multiple client machines. Results show that Barlow
Twins outperforms supervised learning in an unlabeled target domain with
emerging motor faults when the source training data contains very few distinct
categories. Incorporating FL may also provide a slight advantage by diffusing
knowledge of health conditions between machines
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Όλ¬Έ(λ°μ¬) -- μμΈλνκ΅λνμ : 곡과λν κΈ°κ³ν곡곡νλΆ, 2023. 2. μ€λ³λ.Rotating machinery is widely used in many industrial sites, including manufacturing and power generation. Unpredicted failures in these systems can result in huge economic and human losses. To prevent this situation, fault diagnosis studies have gathered much attention, with the goal of operating rotating machines without the occurrence of any unpredicted problems. Fault diagnosis methods aim to accurately detect any abnormality prior to failure and classify the health conditions of the target system. Recently, fault diagnosis studies using deep learning have achieved excellent performance thanks to the ability of new methods to autonomously extract meaningful features.
For this purpose, two types of signals of different resolutions are measured from rotating machinery, specifically: operation signals and vibration signals. Operation signals, which are measured with a low sampling rate, are obtained in real-time and contain various types of condition parameters that enable global monitoring of the system. Vibration signals with a high sampling rate are obtained when an event occurs, not in real-time. Using these signals of different resolutions, two sub-tasks of fault diagnosis β anomaly detection and fault identification β are performed. Anomaly detection, which is conducted with operation signals, is a task to detect abnormalities in a system before those abnormalities develop into a hard failure. This is considered macro-level fault diagnosis. When performing anomaly detection, the normal data is modeled by unsupervised learning, a residual is calculated, and a threshold is determined. If the residual becomes larger than the threshold, the system is regarded as an anomaly condition. Fault identification is performed to classify the health conditions of the system using vibration signals; this is viewed as micro-level fault diagnosis. For fault identification, supervised learning is used to train a deep-learning-based classifier; thus, a large amount of labeled data is required for the training. Since fault data is insufficient in real industrial fields, data augmentation is necessary to augment the fault data. Currently, a variational auto-encoder or a generative adversarial network are the approaches most widely used for data augmentation.
Anomaly detection and fault identification have been studied separately. If both tasks are integrated, macro- and micro-level fault diagnosis can be implemented. However, there are three issues that must be handled to develop a deep-learning-based methodology for macro- and micro-level fault diagnosis. First, conventional anomaly detection methods produce frequent false alarms; in other words, they may indicate a problem even if there is no anomaly in the system. This problem occurs because conventional approaches may model the normal data inadequately or set a wrong threshold; for example, one that does not consider the fluctuations in the normal data. Second, the prior generative-network-based augmentation approach has inborn limitations due to its structural properties. With this method, signals of various lengths cannot be generated because the architecture is fixed. Also, incorrect samples can be generated if the latent vectors are sampled wrongly. The final issue with health classification is that the performance of a classifier can be affected by noise in the input data. Since noise can distort the data distribution, it is difficult for a classifier to correctly classify the noisy data.
Based on the current state of the field, this doctoral dissertation proposes a deep-learning-based methodology for macro- and micro-level fault diagnosis using operation and vibration signals from rotating machinery. The first research thrust proposes new methods for modeling and threshold setting to reduce false alarms related to anomaly detection. The proposed modeling method is developed by applying ensemble and denoising techniques to auto-encoders. Further, a threshold is newly proposed using the joint distribution of the output and the residual. Consequently, the proposed method considers the fluctuations in the normal data, which can significantly reduce false alarms. The second research thrust proposes a new generative network to generate signals of variable lengths. The proposed network, whose input and output are the time and amplitude, respectively, is designed to learn the frequency information of the training data. The proposed method is implemented to reflect the signal processing knowledge, including the use of the Nyquist theorem. After the training is finished, the proposed model can produce signals of various lengths in the desired time range. The proposed approach can also focus on the characteristic frequency components, thanks to attention blocks. The third research thrust proposes a novel training method that simultaneously learns the classification and denoising tasks. In the proposed scheme, multi-task learning is used to allow a classifier to solve the classification and denoising tasks concurrently. The proposed method can be applied to any deep-learning algorithm, regardless of the network type. The classifier that is trained by the proposed method can classify the health conditions, as well as remove noise in the input signals.νμ κΈ°κ³λ μ μ‘° λ° λ°μ κ³Ό κ°μ΄ λ€μν μ°μ
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Έμ΄μ¦λ μ κ±°ν μ μλ€.Chapter 1 Introduction 1
1.1 Motivation 1
1.2 Research Scope and Overview 5
1.3 Dissertation Layout 9
Chapter 2 Technical Background and Literature Review 10
2.1 Fault Diagnosis Methods of Rotating Machinery 10
2.2 Low- and High-resolution Signals from Rotating Machinery 13
2.3 Review of Deep Learning Algorithms 15
2.3.1 One-dimensional Convolutional Neural Network (1D CNN) 16
2.3.2 Long Short-term Memory (LSTM) 17
2.4 Deep-learning-based Macro- and Micro-level Fault Diagnosis Methods 19
2.4.1 Anomaly Detection 23
2.4.2 Data Augmentation 28
2.4.3 Health Classification 32
2.5 Summary and Discussion 35
Chapter 3 Ensemble Denoising Auto-encoder-based Dynamic Threshold (EDAE-DT) for Anomaly Detection 37
3.1 Background: Deep-learning-based Anomaly Detection 39
3.1.1 Conventional Methods to Model the Normal Data 39
3.1.2 Conventional Methods to Set a Threshold 41
3.2 Ensemble Denoising Auto-encoder-based Dynamic Threshold (EDAE-DT) 42
3.3 Performance Evaluation Metrics 47
3.4 Description of the Validation Datasets 50
3.5 Validation of the Proposed Method 58
3.5.1 Case Study 1: Dataset A1 58
3.5.2 Case Study 2: Dataset A2 74
3.5.3 Analysis and Discussion 89
3.6 Summary and Discussion 95
Chapter 4 Frequency-learning Generative Network (FLGN) for Data Augmentation 96
4.1 Background: Fourier Series 97
4.2 Frequency-learning Generative Network (FLGN) 99
4.2.1 Problem Formulation 99
4.2.2 Overall Procedure of FLGN 100
4.2.3 Deep-learning Implementation Details to Reflect Signals Processing Knowledge 105
4.3 Experimental Implementation Setting 106
4.3.1 Hyper-parameter Setting 107
4.3.2 Evaluation Scheme 107
4.4 Description of the Validation Datasets 111
4.5 Validation of the Proposed Method 119
4.5.1 Case Study 1: Simulated Signal 119
4.5.2 Case Study 2: RK4 Testbed Dataset 128
4.5.3 Case Study 3: MAFAULDA 141
4.5.4 Analysis and Discussion 153
4.6 Summary and Discussion 158
Chapter 5 Multi-task Learning of Classification and Denoising (MLCD) for Health Classification 159
5.1 Background: Multi-task Learning 160
5.2 Multi-task Learning of Classification and Denoising (MLCD) 161
5.2.1 Overall Procedure of MLCD 162
5.2.2 Integration with LSTM: MLCD-LSTM 165
5.2.3 Integration with 1D CNN: MLCD-1D CNN 166
5.3 Preprocessing Techniques 170
5.4 Description of the Validation Datasets 172
5.5 Validation of the Proposed Method 176
5.5.1 Case Study 1: MLCD-LSTM 176
5.5.2 Case Study 2: MLCD-1D CNN 183
5.6 Summary and Discussion 190
Chapter 6 Conclusion 191
6.1 Contributions and Significance 191
6.2 Suggestions for Future Research 194
References 196
κ΅λ¬Έ μ΄λ‘ 209λ°
Data-Driven Fault Detection and Reasoning for Industrial Monitoring
This open access book assesses the potential of data-driven methods in industrial process monitoring engineering. The process modeling, fault detection, classification, isolation, and reasoning are studied in detail. These methods can be used to improve the safety and reliability of industrial processes. Fault diagnosis, including fault detection and reasoning, has attracted engineers and scientists from various fields such as control, machinery, mathematics, and automation engineering. Combining the diagnosis algorithms and application cases, this book establishes a basic framework for this topic and implements various statistical analysis methods for process monitoring. This book is intended for senior undergraduate and graduate students who are interested in fault diagnosis technology, researchers investigating automation and industrial security, professional practitioners and engineers working on engineering modeling and data processing applications. This is an open access book
A Framework for the Automated Parameterization of a Sensorless Bearing Fault Detection Pipeline
This study proposes a framework for the automated hyperparameter optimization
of a bearing fault detection pipeline for permanent magnet synchronous motors
(PMSMs) without the need of external sensors. A automated machine learning
(AutoML) pipeline search is performed by means of a genetic optimization to
reduce human induced bias due to inappropriate parameterizations. For this
purpose, a search space is defined, which includes general methods of signal
processing and manipulation as well as methods tailored to the respective task
and domain. The proposed framework is evaluated on the bearing fault detection
use case under real world conditions. Considerations on the generalization of
the deployed fault detection pipelines are also taken into account. Likewise,
attention was paid to experimental studies for evaluations of the robustness of
the fault detection pipeline to variations of the motors working condition
parameters between the training and test domain. The present work contributes
to the research of fault detection on rotating machinery in the following
terms: (1) Reduction of the human induced bias to the data science process,
while still considering expert and task related knowledge, ending in a generic
search approach (2) tackling the bearing fault detection task without the need
for external sensors (sensorless) (3) learning a domain robust fault detection
pipeline applicable to varying motor operating parameters without the need of
re-parameterizations or fine-tuning (4) investigations on working condition
discrepancies with an excessive degree to determine the pipeline limitations
regarding the abstraction of the motor parameters and the pipeline
hyperparametersComment: 8 pages, 4 figures, 5 tables, ieee conference paper template use
Friction, Vibration and Dynamic Properties of Transmission System under Wear Progression
This reprint focuses on wear and fatigue analysis, the dynamic properties of coating surfaces in transmission systems, and non-destructive condition monitoring for the health management of transmission systems. Transmission systems play a vital role in various types of industrial structure, including wind turbines, vehicles, mining and material-handling equipment, offshore vessels, and aircrafts. Surface wear is an inevitable phenomenon during the service life of transmission systems (such as on gearboxes, bearings, and shafts), and wear propagation can reduce the durability of the contact coating surface. As a result, the performance of the transmission system can degrade significantly, which can cause sudden shutdown of the whole system and lead to unexpected economic loss and accidents. Therefore, to ensure adequate health management of the transmission system, it is necessary to investigate the friction, vibration, and dynamic properties of its contact coating surface and monitor its operating conditions
Intelligent Condition Monitoring and Prognostic Methods with Applications to Dynamic Seals in the Oil & Gas Industry
The capital-intensive oil & gas industry invests billions of dollars in equipment annually and it is important to keep the equipment in top operating condition to help maintain efficient process operations and improve the rate of return by predicting failures before incidents. Digitalization has taken over the world with advances in sensor technology, wireless communication and computational capabilities, however oil & gas industry has not taken full advantage of this despite being technology centric.
Dynamic seals are a vital part of reciprocating and rotary equipment such as compressor, pumps, engines, etc. and are considered most frequently failing component. Polymeric seals are increasingly complex and non-linear in behavior and have been the research of interest since 1950s. Most of the prognostic studies on seals are physics-based and requires direct estimation of different physical parameters to assess the degradation of seals, which are often difficult to obtain during operation. Another feasible approach to predict the failure is from performance related sensor data and is termed as data-driven prognostics. The offline phase of this approach is where the performance related data from the component of interest are acquired, pre-processed and artificial intelligence tools or statistical methods are used to model the degradation of a system. The developed models are then deployed online for a real-time condition monitoring. There is a lack of research on the data-driven based tools and methods for dynamic seal prognosis. The primary goal in this dissertation is to develop offline data-driven intelligent condition monitoring and prognostic methods for two types of dynamic seals used in the oil & gas industry, to avoid fatal breakdown of rotary and reciprocating equipment.
Accordingly, the interest in this dissertation lies in developing models to effectively evaluate and classify the running condition of rotary seals; assess the progression of degradation from its incipient to failure and to estimate the remaining useful life (RUL) of reciprocating seals.
First, a data-driven prognostic framework is developed to classify the running condition of rotary seals. An accelerated aging and testing procedure simulating rotary seal operation in oil field is developed to capture the behavior of seals through their cycle of operation until failure. The diagnostic capability of torque, leakage and vibration signal in differentiating the health states of rotary seals using experiments are compared. Since the key features that differentiate the health condition of rotary seals are unknown, an extensive feature extraction in time and frequency domain is carried out and a wrapper-based feature selection approach is used to select relevant features, with Multilayer Perceptron neural network utilized as classification technique. The proposed approach has shown that features extracted from torque and leakage lack a better discriminating power on its own, in classifying the running condition of seals throughout its service life. The classifier built using optimal set of features from torque and leakage collectively has resulted in a high classification accuracy when compared to random forest and logistic regression, even for the data collected at a different operating condition.
Second, a data-driven approach to predict the degradation process of reciprocating seals based on friction force signal using a hybrid Particle Swarm Optimization - Support Vector Machine is presented. There is little to no knowledge on the feature that reflects the degradation of reciprocating seals and on the application of SVM in predicting the future running condition of polymeric components such as seals. Controlled run-to-failure experiments are designed and performed, and data collected from a dedicated experimental set-up is used to develop the proposed approach. A degradation feature with high monotonicity is used as an indicator of seal degradation. The pseudo nearest neighbor is used to determine the essential number of inputs for forecasting the future trend. The most challenging aspect of tuning parameters in SVM is framed in terms of an optimization problem aimed at minimizing the prediction error. The results indicate the effectiveness and better accuracy of the proposed approach when compared to GA-SVM and XGBoost.
Finally, a deep neural network-based approach for estimating remaining useful life of reciprocating seals, using force and leakage signals is presented. Time domain and frequency domain statistical features are extracted from the measurements. An ideal prognostic feature should be well correlated with degradation time, monotonically increasing or decreasing and robust to outliers. The identified metrics namely: monotonicity, correlation and robustness are used to evaluate the goodness of extracted features. Each of the three metric carries a relative importance in the RUL estimation and a weighted linear combination of the metrics are used to rank and select the best set of prognostic features. The redundancy in the selected features is eliminated using Kelley-Gardner-Sutcliffe penalty function-based correlation-clustering algorithm to select a representative feature from each of the clusters. Finally, RUL estimation is modeled using a deep neural network model. Run-to-failure data collected from a reciprocating set-up was used to validate this approach and the findings show that the proposed approach can improve the accuracy of RUL prediction when compared to PSO-SVM and XGBoost regression.
This research has important contribution and implications to rotary and reciprocating seal domain in utilizing sensors along with machine learning algorithms in assessing the health state and prognosis of seals without any direct measurements. This research has paved the way to move from a traditional fail-and-fix to predict-and-prevent approach in maintenance of seals. The findings of this research are foundational for developing an online degradation assessment platform which can remotely monitor the performance degradation of seals and provide action recommendations on maintenance decisions. This would be of great interest to customers and oil field operators to improve equipment utilization, control maintenance cost by enabling just-in-time maintenance and increase rate of return on equipment by predicting failures before incidents
Ship machinery condition monitoring using vibration data through supervised learning
This paper aims to present an integrated methodology for the monitoring of marine machinery using vibration data. Monitoring of machinery is a crucial aspect of maintenance optimisation that is required for the vessel operation to remain sustainable and profitable. The proposed methodology will train models using pre-classified (healthy/faulty) data and then classify new data points using the models developed. For this, vibration points are first acquired, appropriately processed and stored in a database. Specific features are then extracted from the data and stored. These data are then used to train supervised models pertinent to specific machinery components. Finally, new data are compared against the models developed in order to evaluate their condition. The above will provide a flexible but robust framework for the early detection of emerging machinery faults. This will lead to minimisation of ship downtime and increase of the shipβs operability and income through operational enhancement
SensorSCAN: Self-Supervised Learning and Deep Clustering for Fault Diagnosis in Chemical Processes
Modern industrial facilities generate large volumes of raw sensor data during
the production process. This data is used to monitor and control the processes
and can be analyzed to detect and predict process abnormalities. Typically, the
data has to be annotated by experts in order to be used in predictive modeling.
However, manual annotation of large amounts of data can be difficult in
industrial settings.
In this paper, we propose SensorSCAN, a novel method for unsupervised fault
detection and diagnosis, designed for industrial chemical process monitoring.
We demonstrate our model's performance on two publicly available datasets of
the Tennessee Eastman Process with various faults. The results show that our
method significantly outperforms existing approaches (+0.2-0.3 TPR for a fixed
FPR) and effectively detects most of the process faults without expert
annotation. Moreover, we show that the model fine-tuned on a small fraction of
labeled data nearly reaches the performance of a SOTA model trained on the full
dataset. We also demonstrate that our method is suitable for real-world
applications where the number of faults is not known in advance. The code is
available at https://github.com/AIRI-Institute/sensorscan
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